way to tell what version of the client is running

My solution was this.

Change this line in client/bin/xymonclient.sh
CLIENTVERSION="`$XYMONHOME/bin/clientupdate --level`"
to
CLIENTVERSION="`$XYMONHOME/bin/xymon --version`"

This shows up on the info page.
Hostname:          host01
OS:         SunOS host01 5.10 Generic_147440-19 sun4u sparc
SUNW,Sun-Fire-V240
Client S/W:         Xymon version 4.3.10
IP:           10.0.0.70
Of course that doesn't work if you push out the clients from your server.
The client will most probably clobber that file.
But I guess you could change the clientupdate to include this.
I don't use the clientupdate function.

This patch should do the trick as well, using `$XYMON --version` as a
fallback.

-jc